Specific disruption of Lnk in murine endothelial progenitor cells promotes dermal wound healing via enhanced vasculogenesis, activation of myofibroblasts, and suppression of inflammatory cell recruitment

3-Diethylaminopropyl isothiocyanate modified glycol chitosan for constructing mild-acid sensitive electrospinning antibacterial nanofiber membrane

Bacterial infections would cause pathological inflammation and even generate chronic wound. Herein, a ciprofloxacin (Cip)-loaded mild acid-responsive electrospinning nanofiber membrane (NFM) containing 3-diethylaminopropyl isothiocyanate material grafted glycol chitosan (GC-DEAP) was fabricated to prevent bacterial infection against hemostatic and inflammatory phases of wounds. The presence of Cip and GC-DEAP in the objective NFM (PCL/GC-DEAP/Cip) was confirmed through XRD and FTIR. Meanwhile, PCL/GC-DEAP/Cip NFM exhibited high mechanical profiles, suitable water absorption and water vapour transmission ratio. The non-protonated amphiphilic GC-DEAP under pH 7.4 facilitated the formation of uniform and smooth nanofibers with polycaprolactone (PCL) and Cip. However, the GC-DEAP was demonstrated to sharply respond to the mild-acid environment of the wound and effectively be protonated, and thus improved the swelling ability of NFM and triggered burst release of Cip. Due to the combination between protonated GC-DEAP and Cip, PCL/GC-DEAP/Cip NFM achieved attractive antibacterial activity in the mild-acid environment in vitro, and induced more efficient prevention of wound infection and faster wound healing compared with the commercial chitosan dressing. The designed NFM is expected to be a potential smart wound dressing against hemostatic and inflammatory phases with mild-acid specifically strengthened antibacterial features and satisfactory biocompatibility.

A Review Into the Insights of the Role of Endothelial Progenitor Cells on Bone Biology

In addition to its important transport functions, the skeletal system is involved in complex biological activities for the regulation of blood vessels. Endothelial progenitor cells (EPCs), as stem cells of endothelial cells (ECs), possess an effective proliferative capacity and a powerful angiogenic capacity prior to their differentiation. They demonstrate synergistic effects to promote bone regeneration and vascularization more effectively by co-culturing with multiple cells. EPCs demonstrate a significant therapeutic potential for the treatment of various bone diseases by secreting a combination of growth factors, regulating cellular functions, and promoting bone regeneration. In this review, we retrospect the definition and properties of EPCs, their interaction with mesenchymal stem cells, ECs, smooth muscle cells, and immune cells in bone regeneration, vascularization, and immunity, summarizing their mechanism of action and contribution to bone biology. Additionally, we generalized their role and potential mechanisms in the treatment of various bone diseases, possibly indicating their clinical application.

Experimental study of negative pressure wound therapy combined with platelet-rich fibrin for bone-exposed wounds

Aim: To evaluate the efficacy of negative pressure wound therapy (NPWT) combined with platelet-rich fibrin (PRF) in treating bone-exposed wounds and explore its possible mechanism. Materials & methods: A bone-exposed wound was created in a total of 32 healthy Sprague-Dawley rats, which were divided into either control group, NPWT group, PRF group or both (N + P group). The bone-exposed area, skin contraction rate and granulation coverage and the level of growth factors in granulation tissue were determined on days 4, 7 and 10. Results: The N + P group showed significantly higher wound closure rate than that achieved with others respectively. Four factors were significantly higher in N + P group than in the other three groups. Conclusion: Combination of NPWT and PRF can repair bone-exposed wounds effectively and accelerate wound healing.

Improving Chronic Diabetic Wound Healing through an Injectable and Self-Healing Hydrogel with Platelet-Rich Plasma Release

Diabetic skin ulcer is one of the severe complications of diabetes mellitus, which has a high incidence and may cause death or disability. Platelet-rich plasma (PRP) is widely used in the treatment of diabetic wounds due to the effect of growth factors (GFs) derived from it. However, the relatively short half-life of GFs limits their applications in clinics. In addition, the presence of a large amount of proteases in the diabetic wound microenvironment results in the degradation of GFs, which further impedes angiogenesis and diabetic wound healing. In our study, we fabricated a self-healing and injectable hydrogel with a composite of chitosan, silk fibroin, and PRP (CBPGCTS-SF@PRP) for promoting diabetic wound healing. CBPGCTS-SF@PRP could protect PRP from enzymatic hydrolysis, release PRP sustainably, and enhance the chemotaxis of mesenchymal stem cells. The results showed that it could promote the proliferation of repair cells in vitro. Moreover, it could enhance wound healing by expediting collagen deposition, angiogenesis, and nerve repair in a type 2 diabetic rat model and a rat skin defect model. We hope that this study will offer a new treatment for diabetic nonhealing wounds in clinics.

Acellular and cellular approaches to improve diabetic wound healing

Chronic diabetic wounds represent a huge socioeconomic burden for both affected individuals and the entire healthcare system. Although the number of available treatment options as well as our understanding of wound healing mechanisms associated with diabetes has vastly improved over the past decades, there still remains a great need for additional therapeutic options. Tissue engineering and regenerative medicine approaches provide great advantages over conventional treatment options, which are mainly aimed at wound closure rather than addressing the underlying pathophysiology of diabetic wounds. Recent advances in biomaterials and stem cell research presented in this review provide novel ways to tackle different molecular and cellular culprits responsible for chronic and nonhealing wounds by delivering therapeutic agents in direct or indirect ways. Careful integration of different approaches presented in the current article could lead to the development of new therapeutic platforms that can address multiple pathophysiologic abnormalities and facilitate wound healing in patients with diabetes.

Endothelial progenitor cells in age-related vascular remodeling

Accumulating evidence has demonstrated that endothelial progenitor cells (EPCs) could facilitate the reendothelialization of injured arteries by replacing the dysfunctional endothelial cells, thereby suppressing the formation of neointima. Meanwhile, other findings suggest that EPCs may be involved in the pathogenesis of age-related vascular remodeling. This review is presented to summarize the characteristics of EPCs and age-related vascular remodeling. In addition, the role of EPCs in age-related vascular remodeling and possible solutions for improving the therapeutic effects of EPCs in the treatment of age-related diseases are discussed.

Endothelial progenitor cells contribute to neovascularization of non-small cell lung cancer via histone deacetylase 7-mediated cytoskeleton regulation and angiogenic genes transcription

To supply tumor tissues with nutrients and oxygen, endothelial progenitor cells (EPCs) home to tumor sites and contribute to neovascularization. Although the precise mechanism of EPCs-induced neovascularization remains poorly understood in non-small cell lung cancer (NSCLC), histone deacetylase 7 (HDAC7) is considered as a critical regulator. To explore the function of HDAC7 in neovascularization induced by EPCs, tube formation assay, immunofluorescence, microarray, Western blot analysis and animal models were performed. In vitro, HDAC7 abrogation led to the activation of Rho-associated coiled-coil containing protein kinase/myosin light chain 2 pathway concomitant with ERK dephosphorylation, causing the instability of cytoskeleton and collapse of tube formation. In vivo, absence of HDAC7 impaired the vascular lumen integrity and decreased the functional blood perfusion, inhibiting the growth of tumor. At the level of transcription, HDAC7 silencing upregulated antiangiogenic genes and suppressed proangiogenic genes collectively, turning off the angiogenic switch during vessel formation. Taken together, HDAC7 plays a dual role in maintaining the structural and nonstructural functions of EPCs. Our work demonstrates the molecular mechanism by which HDAC7 contributes to the angiogenic property of EPCs and provides a rational basis for specific targeting of antiangiogenic strategies in lung cancer.

Stem cells and heart disease - Brake or accelerator?

After two decades of intensive research and attempts of clinical translation, stem cell based therapies for cardiac diseases are not getting closer to clinical success. This review tries to unravel the obstacles and focuses on underlying mechanisms as the target for regenerative therapies. At present, the principal outcome in clinical therapy does not reflect experimental evidence. It seems that the scientific obstacle is a lack of integration of knowledge from tissue repair and disease mechanisms. Recent insights from clinical trials delineate mechanisms of stem cell dysfunction and gene defects in repair mechanisms as cause of atherosclerosis and heart disease. These findings require a redirection of current practice of stem cell therapy and a reset using more detailed analysis of stem cell function interfering with disease mechanisms. To accelerate scientific development the authors suggest intensifying unified computational data analysis and shared data knowledge by using open-access data platforms.

Cardiac Function Improvement and Bone Marrow Response -: Outcome Analysis of the Randomized PERFECT Phase III Clinical Trial of Intramyocardial CD133+ Application After Myocardial Infarction

OBJECTIVE

The phase III clinical trial PERFECT was designed to assess clinical safety and efficacy of intramyocardial CD133⁺ bone marrow stem cell treatment combined with CABG for induction of cardiac repair.

DESIGN

Multicentre, double-blinded, randomised placebo controlled trial.

SETTING

The study was conducted across six centres in Germany October 2009 through March 2016 and stopped due slow recruitment after positive interim analysis in March 2015.

PARTICIPANTS

Post-infarction patients with chronic ischemia and reduced LVEF (25-50%).

INTERVENTIONS

Eighty-two patients were randomised to two groups receiving intramyocardial application of 5ml placebo or a suspension of 0.5-5×10⁶ CD133⁺.

OUTCOME

Primary endpoint was delta (∆) LVEF at 180days (d) compared to baseline measured in MRI.

FINDINGS (PRESPECIFIED)

Safety (n=77): 180d survival was 100%, MACE n=2, SAE n=49, without difference between placebo and CD133⁺. Efficacy (n=58): The LVEF improved from baseline LVEF 33.5% by +9.6% at 180d, p=0.001 (n=58). Treatment groups were not different in ∆LVEF (ANCOVA: Placebo +8.8% vs. CD133⁺ +10.4%, ∆CD133⁺vs placebo +2.6%, p=0.4).

FINDINGS (POST HOC)

Responders (R) classified by ∆LVEF≥5% after 180d were 60% of the patients (35/58) in both treatment groups. ∆LVEF in ANCOVA was +17.1% in (R) vs. non-responders (NR) (∆LVEF 0%, n=23). NR were characterized by a preoperative response signature in peripheral blood with reduced CD133⁺ EPC (RvsNR: p=0.005) and thrombocytes (p=0.004) in contrast to increased Erythropoeitin (p=0.02), and SH2B3 mRNA expression (p=0.073). Actuarial computed mean survival time was 76.9±3.32months (R) vs. +72.3±5.0months (NR), HR 0.3 [Cl 0.07-1.2]; p=0.067.Using a machine learning 20 biomarker response parameters were identified allowing preoperative discrimination with an accuracy of 80% (R) and 84% (NR) after 10-fold cross-validation.

INTERPRETATION

The PERFECT trial analysis demonstrates that the regulation of induced cardiac repair is linked to the circulating pool of CD133+ EPC and thrombocytes, associated with SH2B3 gene expression. Based on these findings, responders to cardiac functional improvement may be identified by a peripheral blood biomarker signature.

TRIAL REGISTRATION

ClinicalTrials.govNCT00950274.

Role of NADPH Oxidase-4 in Human Endothelial Progenitor Cells

Introduction: Endothelial progenitor cells (EPCs) display a unique ability to promote angiogenesis and restore endothelial function in injured blood vessels. NADPH oxidase 4 (NOX4)-derived hydrogen peroxide (H₂O₂) serves as a signaling molecule and promotes endothelial cell proliferation and migration as well as protecting against cell death. However, the role of NOX4 in EPC function is not completely understood. Methods: EPCs were isolated from human saphenous vein and mammary artery discarded during bypass surgery. NOX4 gene and protein expression in EPCs were measured by real time-PCR and Western blot analysis respectively. NOX4 gene expression was inhibited using an adenoviral vector expressing human NOX4 shRNA (Ad-NOX4i). H₂O₂ production was measured by Amplex red assay. EPC migration was evaluated using a transwell migration assay. EPC proliferation and viability were measured using trypan blue counts. Results: Inhibition of NOX4 using Ad-NOX4i reduced Nox4 gene and protein expression as well as H₂O₂ formation in EPCs. Inhibition of NOX4-derived H₂O₂ decreased both proliferation and migration of EPCs. Interestingly, pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) decreased NOX4 expression and reduced survival of EPCs. However, the survival of EPCs was further diminished by TNF-α in NOX4-knockdown cells, suggesting that NOX4 has a protective role in EPCs. Conclusion: These findings suggest that NOX4-type NADPH oxidase is important for proliferation and migration functions of EPCs and protects against pro-inflammatory cytokine induced EPC death. These properties of NOX4 may facilitate the efficient function of EPCs which is vital for successful neovascularization.